Gauges come on then blow fuse

[rscott1261]

I have 2009 250ss with 2 digital gauges, when i start up the gauges come on for a few seconds show then go to the large S symbol and then fuse blows that run the gauges.
Has anyone seen this and or know what this is?
thanks

[Moonlighter]

Never heard of that happening, it sounds like there is a short in the NMEA2000 network (SMIS gauges based in your description.)

The network is a pretty straightforward thing to check over.

Follow the cable from the gauges and they will connect to a T piece and there will be other T pieces there including one with the power supply and probably a fuse. I would disconnect each T piece and check for corrosion, check that none of the cables have rubbed through anywhere and are shorting.

Then Check that the engine interface cable plugs (the white 4 pin ones where they connect to the engine/wiring harness) are good - they can get corrosion into them from the back, so disconnect and inspect them and the wires going in the back for signs of corrosion. Good chance you will find something amiss there.

I think that corrosion or a physical problem with the wiring as indicated above is the most likely cause of your problem. If you eliminate those issues then it might be time to look at the SmIs gauges themselves. But doubtful given that they do initially start up, and if they had a major short/fault internally they probably wouldn't work at all.

[rscott1261]

Thank you. Could a ground that looses connection every so often cause this as well?

[Moonlighter]

A ground shorting out could cause it, so check the power supply wires to the network power node. The SMIS gauges are powered by the network. So there is a reasonable amount of draw thru the network.

Could be a bad connection there.

Also check that fuse holder, wouldn't be the first time that such a holder has corroded out and caused a short.